As a result, she revelled in the experience of travelling with the Doctor, even though it was usually dangerous.

How she came to be travelling with the Doctor is explained in Black and White.

Chris and Roz travelled with the Doctor for many adventures.

The other, "Dark Sam", never travelled with the Doctor and became a drug user.

Amy and Rory have tried to adjust to normal life without travelling with the Doctor.

This occurred when she stopped traveling with the Doctor, in Fury from the Deep.

Peri hasn't been traveling with the Doctor for long and is charmed by the exciting life he leads.

She first appears in Planet of Fire, after which she travels with the Doctor.

Although she agrees to travel with the Doctor for the time being, she declines his offer of being a full-time companion.

After these events, Fitz decided to travel with the Doctor and Sam, technically on the run from the police.